9NOVEMBER 2022Example 2: PhotovoltaicsDevelopment and fabrication of Photovoltaics show a similar need for multimodal characterization. For example, at the material stage it is important that the material bandgap be engineered to optimally absorb the solar spectrum. Once again, PL is a good technique for determining that property (figure 1a). The photovoltaic effect relies on the efficient movement of charge carriers either to the electrical load for use or to a battery for energy storage. Time-resolved PL is often used to characterize carrier dynamics (figure 1c) or Raman spectra to determine micro crystallinity (which in turn affects carrier dynamics (2a). Finally, in the QA process of the solar cell device one might be interested in measuring the overall device efficiency by measuring the spectral photocurrent response (figure 2b). Although contrived, the above measurements are typical occurrences in the design and manufacture of LED and PV devices and it is also common to see that all these measurements are typically made on different instruments. The novelty in this paper is showing that they can be made on one instrument (the SMS system from HORIBA), resulting in cost savings and adding convenience to the process.Correlative spectroscopy on semiconductor materialsSimple, fast and non-contact microspectroscopy techniques such as the ones described above are usually preferred in semiconductor material characterization, but it is sometimes necessary to use other more complex techniques that are not easy to combine with the above. For example, defect characterization sometime require high spatial resolution (nanometers) that is only available on instruments such as electron (SEM) or AFM microscopes (figure 3a). in those instances, and due to the cost and complexity involved in using a specialized instrument such as an SEM, it is desirable to establish a correlative optical spectroscopy so that that such a defect can be identified in future using a simpler spectroscopic technique rather than doing the measurement on an SEM repeatedly, which can be costly and slow. To achieve this correlation, it becomes necessary to identify a nanoscale feature in the SEM and to also be able to identify the same feature under an optical microspectrometer which can be a laborious and time consuming without some type of coordinate system matching between the two instruments. To facilitate this process automated nanoscale coordinate transformation technologies such as navYX® from HORIBA have been developed to enable fast, accurate and repeatable localization of nanoscale objects between different measurement system (fig 3b)In conclusion, speed, cost minimization and reproducibility are persistent drivers for decision making when it comes to instrumentation choices for semiconductor research and fabrication. In this paper, we introduce a novel modular and multimodal platform that enables the efficient combination of several complementary spectroscopic techniques relevant for semiconductor characterization on one platform. Furthermore, and for when it is necessary to measure across different platforms, we introduce a new coordinate transformation technology that enables the fast and accurate localization of nanoscale features across different measurement and metrology platforms. For further information about the different spectroscopies available on such a platform, please visit www.microscpectroscopy.com and download the application handbook. Fig. 1a Photoluminescence spectra for various semiconductor materials with different bandgaps. (b) Photoluminescence (PL) map of two inch Indium Phosphide water showing distribution of various parameters ­ an indication of homogeneity. (c) measurement of time-resolved PL at three points on an LED die. (d) Spatially resolved electroluminescence of an LEDFig. 2(a) Raman map and spectra (insert) of a possible contaminant flake on the surface of a semiconductor sample. (b) Photocurrent map of a sheet of Silicon PV material showing hot spots (possible defects). The red strip is a piece of the conducting electrode.Fig. 3(a) High resolution cross-sectional view of semiconductor device measured with an SEM with an overlay of Cathodoluminescent centers and wavelengths on the device. A PL measurement of same device could be made a microspectrometer using the NanoGPS tag (blue) shown in figure (b) to quickly navigate to the sample location of interest
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